Control for electric fuel pumps



Oct. 22, 1940. v A. c. KORTE Er AL 2,218,846

CONTROL FOR ELECTRIC FUEL PUMPS Filed Nov. 16, 1939 INVENTORS T ALFREDC. KoRTE KENNETH LANNERI ATTORNEY Patented Oct. 22, 1940 UNITED. STATESPATENT QFFICE CONTROL FOR ELECTRIC FUEL PUMPS Application November 16,1939, Serial No. 304,746

12 Claims.

This invention relates to control means for electrically driven motorvehicle accessories and more particularly to control means forelectrically driven fuel pumps.

It is essential to the satisfactory operation of motor vehicle enginesequipped with current popular type carburetors, that fuel pumps used inconnection therewith operate to supply fuel during all conditions ofengine operation and during cranking to start the engine. It is alsoessential to safety to insure that the pump does not operate at anyother time. Fuel supply to the carburetor during cranking is necessaryeven though the carburetor may have a constant level chamber ofsufficient capacity to permit starting under normal conditions, for thereason that the supply in this chamber is frequently substantiallydepleted by evaporation, and further, this chamber being limited in sizefor practical reasons is usually of insufficient capacity to take careof difficult starting.

In the interest of safety, fuel should not be supplied to the carburetorwhile the engineis inoperative, for the reason that a defective orsticking carburetor float mechanism or leaky inlet valve may permitoverflowing of the constant level chamber, thereby spilling liquid fuelinto the engine induction system causing difficult starting, and whichin sufiicient quantities could cause the engine to be wrecked uponsubsequent cranking. Further, highly inflammable fuel overflowing fromthe constant level chamber through the vent onto an adjacent hot exhaustmanifold is extremely hazardous.

It is the primary object of this invention to provide novel and foolproof means for controlling electrically driven motor vehicle fuel pumpsin accordance. with requirements as heretofore set forth.

The manner in which this object and further objects and advantages whichbecome apparent are accomplished are set forth in the followingdescription and accompanying drawing in which like numerals in thevarious modifications refer to like parts.

Referring to the drawing Figs, 1, 2 and 3 are diagrams of threemodifications of the present invention.

Referring to the drawing, numeral l indicates an electrically drivencentrifugal type fuel pump, similar to the pump disclosed in ourco-pending application, Serial No. 291,588. However, the use of thisparticular pump is not essential to the present invention and the use ofany suitable electrically driven fuel pump is contemplated. A

storage battery is indicated at 2, and a conventional automotive typegenerator adapted to be driven by a motor vehicle engine (not shown) isindicated at 3. A charging lead 22 from the generator to the storagebattery having a conventional reverse current relay l5 interposedtherein is indicated. A starting motor provided for cranking said motorvehicle engine is indicated at 4. A manually operated switch generallyindicated at 5, having a blade 6 which is normally held in the positionshown by the spring I is provided. The switch 5 is further provided withcontacts 8, 9 and Hi.

In the arrangement shown in Fig. 1, the fuel pump and generator areelectrically connected when the switch blade 6 is in the position shown,by lead I I, contact l0,blade 6 and lead l2. A lead l3, contact 8 andlead I! connects the fuel pump 1 to the battery when the switch isdepressed causing the blade 6 to contact with 8. Current for energizingthe starting motor is supplied from the storage battery through lead l3,contact 8, blade 6, contact 9 and head ll when the switch 5 isdepressed.

The operation of the device shown in Fig. 1 is as follows:

Depression of switch 5 will energize starting motor 4 to crank theengine. At this time current is also supplied by the battery to the fuelpump through leads l3 and [2. After the engine has been started theswitch is released and returns to the position as shown by reason ofspring 1. Thereafter, during normal operation of the engine, electricalenergy for operation of the fuel pump is supplied by the generator whichis driven by the engine. The fuel pump will, therefore, cease to operatewhen the engine becomes inoperative. It is assumed in this arrangementthat the generator 3 in Fig. 1 is so constructed and geared with respectto the engine that its output during the lowest engine operating speedis sufficient to operate the electric fuel pump.

It is a fact, however, that in most present day vehicles, the generatorsfurnished therewith do not supply suilicient current for the operationof an electric fuel pump during the lower engine speeds. Thespeed-voltage curve of conventional self-excited shunt wound automotivegenerators, rises very little from zero speed up to a critical speed,whereafter the voltage increases very sharply and the curve rises almostvertically to the regulated maximum voltage. This critical generatorspeed in most cases constitutes an engine speed of approximately 550 R.P. M., or a vehicle speed of about M. P. H.

her. With separate field excitation the generator Referring to Fig. 2which discloses a second form of our invention, we have herein overcomethis difficulty without constructing a costlier generator, by providingseparate excitation of the field winding ll! of the generator 3a. Thisprovision constitutes a storage battery circuit comprising a lead It, amanual switch it, a lead i'i, field winding l8, lead 20, voltageregulator 2i and ground m. The manual switch i9 may be the conventionalignition switch through which ignition devices (not shown) areconnected. The voltage regulator 2| is of conventional type andfunctions to control generator output voltage by varying the fieldstrength in a well known manspeed voltage curve rises from zero to theregulated maximumvoltage in approximately a straight line. As theregulated maximum voltage is reached at approximately the same speed ineither form of field excitation, it will be seen that a substantialincrease in output is gained at speeds below 20 M. P. H. vn'th separatefield excitation. It will be understood of coursethat this gain is paidfor with battery energy and, therefore, the total energy of the systemis not increased. But rather, this arrangement provides a meansdependent on engine operation 'for transmitting energy from the batteryto the fuel pump at the lower speeds by induction, and therefore,functions as a control device.

Apart from the manner of field excitation the device shown in Fig. 2functions similar to the device shown in Fig. i. y

In the third form of our invention as disclosed in Fig. ,3, a solenoidoperated control switch 23 is provided and interposed in a lead ib--2i2*5- i@ti2 from the battery to the fuel pump.

The solenoid winding 26 of switch 23 is energized through lead 2?? bythe generator. The winding 26 is grounded at 28.

The operation of this form of our invention is as follows:

Referring to Fig. 3, upon depressing the switch 5, the starting motor Qwill be energized by the battery through lead ii3Ei-i i, thus crankingthe engine. At this time current will be supplied to the fuel pump bythe battery through lead i3-8@i2. After the engine has been started, theswitch 5 is released and current will be supplied to the fuel pump fromthe battery through lead it--2d--2325i-Eii2 as long asthe enginecontinues to operate and drive the generator, which will energizesolenoid 2d thereby holding switch 23 closed. The separately excitedgenerator field is also used in this arrangement toinsure sumcient flowfrom the generator at low speeds to hold switch 23 closed. It will beunderstood that the switch 28 and also the conven- 1 tional reversecurrent relay iii are normally open, that is to say they are in acircuit breaking position except when suficien't current is passingthrough their respective actuating solenoid windings to close or holdthem closed. It will be further understood that the reverse currentrelay i 5 is so calibrated as to be closed only when the generatoroutput voltage is equal to or above that of the storage battery and thatthe automotive type generator herein considered reaches this output at aspeed which approximates 20 M. P. H. vehicle speed.

We are aware that the present disclosure is subject to variousmodifications and we contemaaraeae plate the use of all which comewithin the scope of the appended claims.

We claim:

1.- In a fuel pump control system for internal combustionengines, anengine cranking motor, a source of power dependent on continuous en gineoperation for driving-the fuel pump, a source of power independent ofcontinuous engine opera- .tion for driving the fuelpump, and controlmeans whereby the fuel pump is caused to be operated by said independentpower source during the operation ofsaid cranking motor, and whereby thefuel pump is caused to operate by said dependent power source duringnormal. engine operation.

2. In a control system for electrically driven internal combustionengine fuel pumps, an electric engine cranking motor, an engine drivengenerator, a storage battery, an electric fuel pump motor, and amanually operated switch device capable of being moved to one positionwhereby said cranking motor and said fuel pump motor are energized bysaid battery and capable of being moved to second position whereby saidfuel pump motor is energized by said generator.

3. In a control system for electrically driven internal combustionengine fuel pumps, an electric starting motor, an electric engine driven*generator, a storage battery, an electric fuel pump motor, and a switchdevice, said switch being movable to one position whereby said battery,said starting motor and said fuel pump motor are electrically connected,and yieldable means for normally urging said switch to another positionwhereby said generatpr and said fuel. pump motor are electricallyconnected.

- 4. In a control system for electrically driven automotive fuel pumps,an electric fuel pump motor, an internal combustion engine, a storagebattery, and means controlled by said battery and dependent upon theoperation of said engine for transmitting electrical energy to said fuelpump motor by induction for the operation thereof.

5. In a control system for electrically driven automotive fuel pumps, aninterna combustion engine, an electrical fuel pump circuit comprising astorage battery, an electric fuel pumpmotor, and a normally open controlswitch, an electromagnet constructed and arranged to move said controlswitch-to a circuit closing position when energized, and meanscontrolled by said battery and dependent upon the operation of saidengine for energizing said electromagnet.

6. In a control system for electrically driven automotive fuel pumps, aninternal combustion engine, an electrical fuel pump circuit, comprisinga storage battery, an electric fuel pump motor and a normally opencontrol switch, an electromagnet constructed and arranged to move saidcontrol switch to a circuit closing position when energized, and meanscontrolled by said battery and dependent upon the operation of saidengine for transmitting electrical energy to said electromagnet byinduction.

- '7. In a control system for electrically driven automotive fuel pumps,an internal combustion engine, an electrical circuit comprising astorage battery, an electric fuel pump motor and a normally open controlswitch, a second electrical circuit comprising a generator controlled bysaid battery and arranged to be driven by said engine, and anelectromagnet, said electromagnet being constructed and arranged tomove. said control switch to a circuit closing pomtion when energized.

8. In a control system for electrically driven automotive fuel pumps, aninternal combustion engine, an electric starting motor for cranking saidengine, an electrically driven fuel pump for supplying fuel to saidengine, a storage battery, an electrical circuit connecting said storagebattery and said fuel pump, a normally open switch in said circuit, anelectromagnet for closing said I switch, means dependent upon theoperation of said engine for energizing said electromagnet, a branchedcircuit for connecting said starting motor and said fuel pump to saidbattery, and a switchfor opening and closing said branched circuit, saidlast mentioned switch being normally held in a circuit open position byyieldable means.

9. In combination, an internal combustion engine, a generator comprisinga field winding and an engine driven armature, a storage battery and anelectric fuel pump, a charging lead connectinggenerator having a fieldexcited by said battery and an armature rotated by said engine, and acircuit comprising said fuel pump and said armature.

, 11. In a control system for electrically driven automotive fuel pumps,an internal combustion engine, a storage battery, a generator having afield excited by said battery and an armature rotated by said engine, acircuit comprising an electric fuel pump motor and said armature, acircuit comprising said storage battery and said fuel pump motor andswitch means for alternately disconnecting said fuel pump from saidbattery and from said armature.

l2. Ina control system for electrically driven automotive fuel pumps, aninternal combustion engine, an electric engine cranking motor, a storagebattery, a generator having a field excited by-said battery and anarmature rotated by said engine, a circuit comprising said crankingmotor and said battery, a circuit comprising an electric fuel pump motorand said generator armature, a circuit comprising said fuel pump motorand said battery, and a switch device whereby said cranking motor andsaid .fuel pump motor can be simultaneously connected to said batteryand said fuel pump motor disconnected from said armature.

' ALFRED C. KOR'IE.

mm LANNERT.

